Overview of JAK-STAT signaling in host defense and cellular homeostasis

Type I and II cytokines bind their receptors with subsequent intracellular signaling via the JAK-STAT pathway. The cytoplasmic domain of cytokine receptors associates with various JAKs (JAK1, JAK2, JAK3, and nonreceptor TYK2). These kinases act via autophosphorylation as well as STAT phosphorylation. Key host inflammatory responses are mediated through these interactions, including those that lead to autoimmune inflammatory diseases such as rheumatoid arthritis. Shown here are the signaling pathways of a select group of cytokines, as well as cytokine receptor dimerization and their association with JAKs.